Metal-assisted delayed fluorescent emitters employing pyrido-pyrrolo-acridine and analogues

ABSTRACT

Metal-assisted delayed fluorescent (MADF) emitters including cyclic tetradentate platinum (II) and palladium (II) complexes employing 8H-pyrido[3′,2′:4,5]-pyrrolo[3,2,1-de]acridine and its analogues. These complexes provide improved color purity and enhanced operational stability and are suitable for luminescent labels, emitters for organic light emitting diodes (OLEDs), and lighting applications.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a 35 U.S.C. § 371 national stage patent application of International Patent Application No. PCT/US2018/015506, filed Jan. 26, 2018, which claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application Ser. No. 62/451,574, filed Jan. 27, 2017, all of which are incorporated herein by reference in their entireties.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with government support under DE-EE0007090 awarded by the Department of Energy. The government has certain rights in the invention.

TECHNICAL FIELD

This invention relates to metal-assisted delayed fluorescent (MADF) emitters including cyclic tetradentate platinum (II) and palladium (II) complexes employing 8H-pyrido[3′,2′:4,5]-pyrrolo[3,2,1-de]acridine and its analogues.

BACKGROUND

Compounds capable of absorbing and/or emitting light can be suited for use in a wide variety of optical and electroluminescent devices, including, for example, photo-absorbing devices such as solar- and photo-sensitive devices, organic light emitting diodes (OLEDs), photo-emitting devices, or devices capable of both photo-absorption and emission and as markers for bio-applications. Much research has been devoted to the discovery and optimization of organic and organometallic materials for using in optical and electroluminescent devices. Generally, research in this area aims to accomplish a number of goals, including improvements in absorption and emission efficiency and improvements in the stability of devices, as well as improvements in processing ability.

Despite significant advances in research devoted to optical and electro-optical materials (e.g., red and green phosphorescent organometallic materials are commercially available and have been used as phosphors in organic light emitting diodes (OLEDs), lighting, and advanced displays), many currently available materials exhibit a number of disadvantages, including poor processing ability, inefficient emission or absorption, and less than ideal stability, among others.

Good blue emitters are particularly scarce, with one challenge being the stability of the blue devices. The choice of the host materials has an impact on the stability and the efficiency of the devices. The lowest triplet excited state energy of the blue phosphors is greater than that of the red and green phosphors, which suggests that the lowest triplet excited state energy of host materials for the blue devices should be even higher. Thus, one of the problems is that there are limited host materials to be used for the blue devices. Accordingly, a need exists for new materials which exhibit improved performance in optical emitting and absorbing applications.

SUMMARY

Metal-assisted delayed fluorescent emitters represented by General Formulas I-IV are disclosed.

In General Formulas I-IV:

M is Pt (II) or Pd (II);

each of V^(1a)-V^(1f), V^(2a)-V^(2f), V^(3a)-V^(3f), V^(4a)-V^(4f), V^(5a)-V^(5f), and V^(6a)-V^(6f), if present, is independently N, C, P, O, S or Si;

each of X, X¹, X², X³, and X⁴ is independently present or absent, and each X, X¹, X², X³, and X⁴ present independently represents a single bond, CR⁷R⁸, C═O, SiR⁷R⁸, GeR⁷R⁸, NR⁷, PR⁷, PR⁷R⁸, R⁷P═O, AsR⁷, R⁷As═O, O, S, S═O, SO₂, Se, Se═O, SeO₂, BR⁷, BR⁷R⁸, AlR⁷, AlR⁷R⁸, R⁷Bi═O, or BiR⁷;

each of Y¹ and Y², if present, is independently CR, SiR, GeR, N, NR, P, P═O, As, As═O, B, BR, Al, AlR, Bi═O, or Bi; and

each of R, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ is independently absent or present as a single substituent or multiple substituents, valency permitting, and each R, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ present independently represents deuterium, halogen, hydroxyl, thiol, nitro, cyano, nitrile, isonitrile, sulfinyl, mercapto, sulfo, carboxyl, hydrazino; substituted or unsubstituted: aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl, alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino, monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester, alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide, silyl, polymeric; or any conjugate or combination thereof.

The complexes of General Formulas I-IV provide improved color purity and enhanced operational stability, and reduce or eliminate potential strong intermolecular interactions. These complexes are suitable for luminescent labels, emitters for organic light emitting diodes (OLEDs), and lighting applications.

The details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a cross section of an exemplary organic light emitting diode (OLED).

FIG. 2 shows a general synthetic procedure for complexes disclosed herein.

FIG. 3 shows emission spectra of PdONac3 in CH₂Cl₂ at room temperature and in tetrahydro-2-methylfuran at 77K.

FIG. 4 shows emission spectra of PtNacONac in CH₂Cl₂ at room temperature and in tetrahydro-2-methylfuran at 77K.

DETAILED DESCRIPTION

Metal-assisted delayed fluorescent emitters represented by General Formulas I-IV are disclosed.

In General Formulas I-IV:

M is Pt (II) or Pd (II);

each of V^(1a)-V^(1f), V^(2a)-V^(2f), V^(3a)-V^(3f), V^(4a)-V^(4f), V^(5a)-V^(5f), and V^(6a)-V^(6f), if present, is independently N, C, P, O, S or Si;

each of X, X¹, X², X³, and X⁴ is independently present or absent, and each X, X¹, X², X³, and X⁴ present independently represents a single bond, CR⁷R⁸, C═O, SiR⁷R⁸, GeR⁷R⁸, NR⁷, PR⁷, PR⁷R⁸, R⁷P═O, AsR⁷, R⁷As═O, O, S, S═O, SO₂, Se, Se═O, SeO₂, BR⁷, BR⁷R⁸, AlR⁷, AlR⁷R⁸, R⁷Bi═O, or BiR⁷;

each of Y¹ and Y², if present, is independently CR, SiR, GeR, N, NR, P, P═O, As, As═O, B, BR, Al, AlR, Bi═O, or Bi; and

each of R, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ is independently absent or present as a single substituent or multiple substituents, valency permitting, and each R, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ present independently represents deuterium, halogen, hydroxyl, thiol, nitro, cyano, nitrile, isonitrile, sulfinyl, mercapto, sulfo, carboxyl, hydrazino; substituted or unsubstituted: aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl, alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino, monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester, alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide, silyl, polymeric; or any conjugate or combination thereof.

Examples of complexes of General Formulas I-IV include the following structures, where each of R⁹, R¹⁰, R¹¹, and R¹², if present, independently represents deuterium, halogen, hydroxyl, thiol, nitro, cyano, nitrile, isonitrile, sulfinyl, mercapto, sulfo, carboxyl, hydrazino; substituted or unsubstituted: aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl, alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino, monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester, alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide, silyl, polymeric; or any conjugate or combination thereof.

It is to be understood that the present complexes, devices, and/or methods are not limited to specific synthetic methods unless otherwise specified, or to particular reagents unless otherwise specified, as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of complexes of the present disclosure, example methods and materials are now described.

Disclosed are the components to be used to prepare the compositions of this disclosure as well as the compositions themselves to be used within the methods disclosed herein. These and other materials are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these materials are disclosed that while specific reference of each various individual and collective combinations and permutation of these compounds cannot be explicitly disclosed, each is specifically contemplated and described herein. For example, if a particular compound is disclosed and discussed and a number of modifications that can be made to a number of molecules including the compounds are discussed, specifically contemplated is each and every combination and permutation of the compound and the modifications that are possible unless specifically indicated to the contrary. Thus, if a class of molecules A, B, and C is disclosed as well as a class of molecules D, E, and F and an example of a combination molecule, A-D is disclosed, then even if each is not individually recited each is individually and collectively contemplated meaning combinations A-E, A-F, B-D, B-E, B-F, C-D, C-E, and C-F are considered disclosed. Likewise, any subset or combination of these is also disclosed. Thus, for example, the sub-group of A-E, B-F, and C-E would be considered disclosed. This concept applies to all aspects of this application including, but not limited to, steps in methods of making and using the compositions disclosed herein. Thus, if there are a variety of additional steps that can be performed it is understood that each of these additional steps can be performed with any specific embodiment or combination of embodiments of the methods described herein.

As referred to herein, a linking atom or group connects two atoms such as, for example, an N atom and a C atom. A linking atom or group is in one aspect disclosed as L¹, L², L³, etc. herein. The linking atom can optionally, if valency permits, have other chemical moieties attached. For example, in one aspect, an oxygen would not have any other chemical groups attached as the valency is satisfied once it is bonded to two groups (e.g., N and/or C groups). In another aspect, when carbon is the linking atom, two additional chemical moieties can be attached to the carbon. Suitable chemical moieties include amine, amide, thiol, aryl, heteroaryl, cycloalkyl, and heterocyclyl moieties. The term “cyclic structure” or the like terms used herein refer to any cyclic chemical structure which includes, but is not limited to, aryl, heteroaryl, cycloalkyl, cycloalkenyl, heterocyclyl, carbene, and N-heterocyclic carbene.

As used herein, the term “substituted” is contemplated to include all permissible substituents of organic compounds. In a broad aspect, the permissible substituents include acyclic and cyclic, branched and unbranched, carbocyclic and heterocyclic, and aromatic and nonaromatic substituents of organic compounds. Illustrative substituents include, for example, those described below. The permissible substituents can be one or more and the same or different for appropriate organic compounds. For purposes of this disclosure, the heteroatoms, such as nitrogen, can have hydrogen substituents and/or any permissible substituents of organic compounds described herein which satisfy the valences of the heteroatoms. This disclosure is not intended to be limited in any manner by the permissible substituents of organic compounds. Also, the terms “substitution” or “substituted with” include the implicit proviso that such substitution is in accordance with permitted valence of the substituted atom and the substituent, and that the substitution results in a stable compound, e.g., a compound that does not spontaneously undergo transformation such as by rearrangement, cyclization, elimination, etc. It is also contemplated that, in certain aspects, unless expressly indicated to the contrary, individual substituents can be further optionally substituted (i.e., further substituted or unsubstituted).

In defining various terms, “A¹”, “A²”, “A³”, “A⁴” and “A⁵” are used herein as generic symbols to represent various specific substituents. These symbols can be any substituent, not limited to those disclosed herein, and when they are defined to be certain substituents in one instance, they can, in another instance, be defined as some other substituents.

The term “alkyl” as used herein is a branched or unbranched saturated hydrocarbon group of 1 to 24 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, isopentyl, s-pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, eicosyl, tetracosyl, and the like. The alkyl group can be cyclic or acyclic. The alkyl group can be branched or unbranched. The alkyl group can also be substituted or unsubstituted. For example, the alkyl group can be substituted with one or more groups including, but not limited to, alkyl, cycloalkyl, alkoxy, amino, ether, halide, hydroxy, nitro, silyl, sulfo-oxo, or thiol, as described herein. A “lower alkyl” group is an alkyl group containing from one to six (e.g., from one to four) carbon atoms.

Throughout the specification “alkyl” is generally used to refer to both unsubstituted alkyl groups and substituted alkyl groups; however, substituted alkyl groups are also specifically referred to herein by identifying the specific substituent(s) on the alkyl group. For example, the term “halogenated alkyl” or “haloalkyl” specifically refers to an alkyl group that is substituted with one or more halide, e.g., fluorine, chlorine, bromine, or iodine. The term “alkoxyalkyl” specifically refers to an alkyl group that is substituted with one or more alkoxy groups, as described below. The term “alkylamino” specifically refers to an alkyl group that is substituted with one or more amino groups, as described below, and the like. When “alkyl” is used in one instance and a specific term such as “alkylalcohol” is used in another, it is not meant to imply that the term “alkyl” does not also refer to specific terms such as “alkylalcohol” and the like.

This practice is also used for other groups described herein. That is, while a term such as “cycloalkyl” refers to both unsubstituted and substituted cycloalkyl moieties, the substituted moieties can, in addition, be specifically identified herein; for example, a particular substituted cycloalkyl can be referred to as, e.g., an “alkylcycloalkyl.” Similarly, a substituted alkoxy can be specifically referred to as, e.g., a “halogenated alkoxy,” a particular substituted alkenyl can be, e.g., an “alkenylalcohol,” and the like. Again, the practice of using a general term, such as “cycloalkyl,” and a specific term, such as “alkylcycloalkyl,” is not meant to imply that the general term does not also include the specific term.

The term “cycloalkyl” as used herein is a non-aromatic carbon-based ring composed of at least three carbon atoms. Examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, norbornyl, and the like. The term “heterocycloalkyl” is a type of cycloalkyl group as defined above, and is included within the meaning of the term “cycloalkyl,” where at least one of the carbon atoms of the ring is replaced with a heteroatom such as, but not limited to, nitrogen, oxygen, sulfur, or phosphorus. The cycloalkyl group and heterocycloalkyl group can be substituted or unsubstituted. The cycloalkyl group and heterocycloalkyl group can be substituted with one or more groups including, but not limited to, alkyl, cycloalkyl, alkoxy, amino, ether, halide, hydroxy, nitro, silyl, sulfo-oxo, or thiol as described herein.

The terms “alkoxy” and “alkoxyl” as used herein to refer to an alkyl or cycloalkyl group bonded through an ether linkage; that is, an “alkoxy” group can be defined as —OA¹ where A¹ is alkyl or cycloalkyl as defined above. “Alkoxy” also includes polymers of alkoxy groups as just described; that is, an alkoxy can be a polyether such as —OA-OA² or —OA¹-(OA²)_(a)-OA³, where “a” is an integer of from 1 to 200 and A¹, A², and A³ are alkyl and/or cycloalkyl groups.

The term “alkenyl” as used herein is a hydrocarbon group of from 2 to 24 carbon atoms with a structural formula containing at least one carbon-carbon double bond. Asymmetric structures such as (A¹A²)C═C(A³A⁴) are intended to include both the E and Z isomers. This can be presumed in structural formulae herein wherein an asymmetric alkene is present, or it can be explicitly indicated by the bond symbol C═C. The alkenyl group can be substituted with one or more groups including, but not limited to, alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone, azide, nitro, silyl, sulfo-oxo, or thiol, as described herein.

The term “cycloalkenyl” as used herein is a non-aromatic carbon-based ring composed of at least three carbon atoms and containing at least one carbon-carbon double bound, i.e., C═C. Examples of cycloalkenyl groups include, but are not limited to, cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclopentadienyl, cyclohexenyl, cyclohexadienyl, norbornenyl, and the like. The term “heterocycloalkenyl” is a type of cycloalkenyl group as defined above, and is included within the meaning of the term “cycloalkenyl,” where at least one of the carbon atoms of the ring is replaced with a heteroatom such as, but not limited to, nitrogen, oxygen, sulfur, or phosphorus. The cycloalkenyl group and heterocycloalkenyl group can be substituted or unsubstituted. The cycloalkenyl group and heterocycloalkenyl group can be substituted with one or more groups including, but not limited to, alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone, azide, nitro, silyl, sulfo-oxo, or thiol as described herein.

The term “alkynyl” as used herein is a hydrocarbon group of 2 to 24 carbon atoms with a structural formula containing at least one carbon-carbon triple bond. The alkynyl group can be unsubstituted or substituted with one or more groups including, but not limited to, alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone, azide, nitro, silyl, sulfo-oxo, or thiol, as described herein.

The term “cycloalkynyl” as used herein is a non-aromatic carbon-based ring composed of at least seven carbon atoms and containing at least one carbon-carbon triple bound. Examples of cycloalkynyl groups include, but are not limited to, cycloheptynyl, cyclooctynyl, cyclononynyl, and the like. The term “heterocycloalkynyl” is a type of cycloalkenyl group as defined above, and is included within the meaning of the term “cycloalkynyl,” where at least one of the carbon atoms of the ring is replaced with a heteroatom such as, but not limited to, nitrogen, oxygen, sulfur, or phosphorus. The cycloalkynyl group and heterocycloalkynyl group can be substituted or unsubstituted. The cycloalkynyl group and heterocycloalkynyl group can be substituted with one or more groups including, but not limited to, alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone, azide, nitro, silyl, sulfo-oxo, or thiol as described herein.

The term “aryl” as used herein is a group that contains any carbon-based aromatic group including, but not limited to, benzene, naphthalene, phenyl, biphenyl, phenoxybenzene, and the like. The term “aryl” also includes “heteroaryl,” which is defined as a group that contains an aromatic group that has at least one heteroatom incorporated within the ring of the aromatic group. Examples of heteroatoms include, but are not limited to, nitrogen, oxygen, sulfur, and phosphorus. Likewise, the term “non-heteroaryl,” which is also included in the term “aryl,” defines a group that contains an aromatic group that does not contain a heteroatom. The aryl group can be substituted or unsubstituted. The aryl group can be substituted with one or more groups including, but not limited to, alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone, azide, nitro, silyl, sulfo-oxo, or thiol as described herein. The term “biaryl” is a specific type of aryl group and is included in the definition of “aryl.” Biaryl refers to two aryl groups that are bound together via a fused ring structure, as in naphthalene, or are attached via one or more carbon-carbon bonds, as in biphenyl.

The term “aldehyde” as used herein is represented by the formula —C(O)H. Throughout this specification “C(O)” is a short hand notation for a carbonyl group, i.e., C═O.

The terms “amine” or “amino” as used herein are represented by the formula —NA¹A², where A¹ and A² can be, independently, hydrogen or alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein.

The term “alkylamino” as used herein is represented by the formula —NH(-alkyl) where alkyl is a described herein. Representative examples include, but are not limited to, methylamino group, ethylamino group, propylamino group, isopropylamino group, butylamino group, isobutylamino group, (sec-butyl)amino group, (tert-butyl)amino group, pentylamino group, isopentylamino group, (tert-pentyl)amino group, hexylamino group, and the like.

The term “dialkylamino” as used herein is represented by the formula —N(-alkyl)₂ where alkyl is a described herein. Representative examples include, but are not limited to, dimethylamino group, diethylamino group, dipropylamino group, diisopropylamino group, dibutylamino group, diisobutylamino group, di(sec-butyl)amino group, di(tert-butyl)amino group, dipentylamino group, diisopentylamino group, di(tert-pentyl)amino group, dihexylamino group, N-ethyl-N-methylamino group, N-methyl-N-propylamino group, N-ethyl-N-propylamino group and the like.

The term “carboxylic acid” as used herein is represented by the formula —C(O)OH.

The term “ester” as used herein is represented by the formula —OC(O)A¹ or —C(O)OA¹, where A¹ can be alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein. The term “polyester” as used herein is represented by the formula -(A¹O(O)C-A²-C(O)O)_(a)— or -(A¹O(O)C-A²-OC(O))_(a)—, where A¹ and A² can be, independently, an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group described herein and “a” is an integer from 1 to 500. “Polyester” is as the term used to describe a group that is produced by the reaction between a compound having at least two carboxylic acid groups with a compound having at least two hydroxyl groups.

The term “ether” as used herein is represented by the formula A¹OA², where A¹ and A² can be, independently, an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group described herein. The term “polyether” as used herein is represented by the formula -(A¹O-A²O)_(a)—, where A¹ and A² can be, independently, an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group described herein and “a” is an integer of from 1 to 500. Examples of polyether groups include polyethylene oxide, polypropylene oxide, and polybutylene oxide.

The term “halide” or “halo” as used herein refers to the halogens fluorine, chlorine, bromine, and iodine.

The term “heterocyclyl,” as used herein refers to single and multi-cyclic non-aromatic ring systems and “heteroaryl as used herein refers to single and multi-cyclic aromatic ring systems: in which at least one of the ring members is other than carbon. The terms includes azetidine, dioxane, furan, imidazole, isothiazole, isoxazole, morpholine, oxazole, oxazole, including, 1,2,3-oxadiazole, 1,2,5-oxadiazole and 1,3,4-oxadiazole, piperazine, piperidine, pyrazine, pyrazole, pyridazine, pyridine, pyrimidine, pyrrole, pyrrolidine, tetrahydrofuran, tetrahydropyran, tetrazine, including 1,2,4,5-tetrazine, tetrazole, including 1,2,3,4-tetrazole and 1,2,4,5-tetrazole, thiadiazole, including, 1,2,3-thiadiazole, 1,2,5-thiadiazole, and 1,3,4-thiadiazole, thiazole, thiophene, triazine, including 1,3,5-triazine and 1,2,4-triazine, triazole, including, 1,2,3-triazole, 1,3,4-triazole, and the like.

The term “hydroxyl” as used herein is represented by the formula —OH.

The term “ketone” as used herein is represented by the formula A¹C(O)A², where A¹ and A² can be, independently, an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein.

The term “azide” as used herein is represented by the formula —N₃.

The term “nitro” as used herein is represented by the formula —NO₂.

The term “nitrile” as used herein is represented by the formula —CN.

The term “silyl” as used herein is represented by the formula —SiA¹A²A³, where A¹, A², and A³ can be, independently, hydrogen or an alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein.

The term “sulfo-oxo” as used herein is represented by the formulas —S(O)A¹, —S(O)₂A¹, —OS(O)₂A¹, or —OS(O)₂OA¹, where A¹ can be hydrogen or an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein.

Throughout this specification “S(O)” is a short hand notation for S═O. The term “sulfonyl” is used herein to refer to the sulfo-oxo group represented by the formula —S(O)₂A¹, where Al can be hydrogen or an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein. The term “sulfone” as used herein is represented by the formula A¹S(O)₂A², where A¹ and A² can be, independently, an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein. The term “sulfoxide” as used herein is represented by the formula A¹S(O)A², where A¹ and A² can be, independently, an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein.

The term “thiol” as used herein is represented by the formula —SH.

“R,” “R¹,” “R²,” “R³,”, “R^(n),” where n is an integer, as used herein can, independently, possess one or more of the groups listed above. For example, if R¹ is a straight chain alkyl group, one of the hydrogen atoms of the alkyl group can optionally be substituted with a hydroxyl group, an alkoxy group, an alkyl group, a halide, and the like. Depending upon the groups that are selected, a first group can be incorporated within second group or, alternatively, the first group can be pendant (i.e., attached) to the second group. For example, with the phrase “an alkyl group comprising an amino group,” the amino group can be incorporated within the backbone of the alkyl group. Alternatively, the amino group can be attached to the backbone of the alkyl group. The nature of the group(s) that is (are) selected will determine if the first group is embedded or attached to the second group.

Compounds described herein may contain “optionally substituted” moieties. In general, the term “substituted,” whether preceded by the term “optionally” or not, means that one or more hydrogens of the designated moiety are replaced with a suitable substituent. Unless otherwise indicated, an “optionally substituted” group may have a suitable substituent at each substitutable position of the group, and when more than one position in any given structure may be substituted with more than one substituent selected from a specified group, the substituent may be either the same or different at every position. Combinations of substituents envisioned by this disclosure are preferably those that result in the formation of stable or chemically feasible compounds. In is also contemplated that, in certain aspects, unless expressly indicated to the contrary, individual substituents can be further optionally substituted (i.e., further substituted or unsubstituted).

In some aspects, a structure of a compound can be represented by a formula:

which is understood to be equivalent to a formula:

wherein n is typically an integer. That is, R^(n) is understood to represent five independent substituents, R^(n(a)), R^(n(b)), R^(n(c)), R^(n(d)), R^(n(e)). By “independent substituents,” it is meant that each R substituent can be independently defined. For example, if in one instance R^(n)(a) is halogen, then R^(n(b)) is not necessarily halogen in that instance.

Several references to R¹, R², R³, R⁴, R⁵, R⁶, etc. are made in chemical structures and moieties disclosed and described herein. Any description of R¹, R², R³, R⁴, R⁵, R⁶, etc. in the specification is applicable to any structure or moiety reciting R¹, R², R³, R⁴, R⁵, R⁶, etc. respectively.

Opto-electronic devices that make use of organic materials are becoming increasingly desirable for a number of reasons. Many of the materials used to make such devices are relatively inexpensive, so organic opto-electronic devices have the potential for cost advantages over inorganic devices. In addition, the inherent properties of organic materials, such as their flexibility, may make them well suited for particular applications such as fabrication on a flexible substrate. Examples of organic opto-electronic devices include OLEDs, organic phototransistors, organic photovoltaic cells, and organic photodetectors. For OLEDs, the organic materials may have performance advantages over conventional materials. For example, the wavelength at which an organic emissive layer emits light may generally be readily tuned with appropriate dopants.

Metal complexes of the present disclosure have improved the color purity, enhanced operational stability as well as elimination of the potential intermolecular interaction. The iridium (III) complexes described herein are useful for full color displays and lighting applications.

The complexes disclosed herein are suited for use in a wide variety of devices, including, for example, optical and electro-optical devices, including, for example, photo-absorbing devices such as solar- and photo-sensitive devices, OLEDs, photo-emitting devices, or devices capable of both photo-absorption and emission and as markers for bio-applications.

Also disclosed herein are compositions including one or more complexes disclosed herein. The present disclosure provides light emitting device that include one or more complexes or compositions described herein. The light emitting device can be an OLED (e.g., a phosphorescent OLED device). The present disclosure also provides a photovoltaic device comprising one or more complexes or compositions described herein. Further, the present disclosure also provides a luminescent display device comprising one or more complexes or compositions described herein.

Compounds described herein can be used in a light emitting device such as an OLED. FIG. 1 depicts a cross-sectional view of an OLED 100. OLED 100 includes substrate 102, anode 104, hole-transporting material(s) (HTL) 106, light processing material 108, electron-transporting material(s) (ETL) 110, and a metal cathode layer 112. Anode 104 is typically a transparent material, such as indium tin oxide. Light processing material 108 may be an emissive material (EML) including an emitter and a host.

In various aspects, any of the one or more layers depicted in FIG. 1 may include indium tin oxide (ITO), poly(3,4-ethylenedioxythiophene) (PEDOT), polystyrene sulfonate (PSS), N,N′-di-1-naphthyl-N,N-diphenyl-1,1′-biphenyl-4,4′diamine (NPD), 1,1-bis((di-4-tolylamino)phenyl)cyclohexane (TAPC), 2,6-Bis(N-carbazolyl)pyridine (mCpy), 2,8-bis(diphenylphosphoryl)dibenzothiophene (PO15), LiF, Al, or a combination thereof.

Light processing material 108 may include one or more compounds of the present disclosure optionally together with a host material. The host material can be any suitable host material known in the art. The emission color of an OLED is determined by the emission energy (optical energy gap) of the light processing material 108, which can be tuned by tuning the electronic structure of the emitting compounds, the host material, or both. Both the hole-transporting material in the HTL layer 106 and the electron-transporting material(s) in the ETL layer 110 may include any suitable hole-transporter known in the art. FIG. 2 shows a general synthetic procedure for complexes disclosed herein. As shown in FIG. 2 , the relevant ligands are synthesized via a copper-catalyzed coupling reaction between brominated pyrido-pyrrolo-acridine and pyrido-pyrrolo-acridine with “X” as a substituent. Refluxing the corresponding ligand and selected metal salt (e.g., platinum or palladium metal salt) in acetic acid yields the desired pyrido-pyrrolo-acridine based complex.

EXAMPLES

The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compounds, compositions, articles, devices and/or methods claimed herein are made and evaluated, and are intended to be purely exemplary and are not intended to be limiting in scope. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.), but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in ° C. or is at ambient temperature, and pressure is at or near atmospheric.

Various methods for the preparation of the compounds described herein are recited in the examples. These methods are provided to illustrate various methods of preparation, but are not intended to limit any of the methods recited herein. Accordingly, one of skill in the art in possession of this disclosure could readily modify a recited method or utilize a different method to prepare one or more of the compounds described herein. The following aspects are only exemplary and are not intended to be limiting in scope. Temperatures, catalysts, concentrations, reactant compositions, and other process conditions can vary, and one of skill in the art, in possession of this disclosure, could readily select appropriate reactants and conditions for a desired complex.

¹H spectra were recorded at 400 MHz and 500 MHz on Varian Liquid-State NMR instruments in DMSO-d6 solutions and chemical shifts were referenced to residual protiated solvent. ¹H NMR spectra were recorded with tetramethylsilane (δ=0.00 ppm) as internal reference. The following abbreviations (or combinations thereof) were used to explain ¹H NMR multiplicities: s=singlet, d=doublet, t=triplet, q=quartet, p=quintet, m=multiplet, br=broad.

Example 1. Synthesis of PdONac3 Synthesis of 8,8-dimethyl-11-(3-(pyridin-2-yl)phenoxy)-8H pyrido[3′,2′:4,5]pyrrolo[3,2,1-de]acridine (ONac3 Ligand)

8,8-dimethyl-8H-pyrido[3′,2″: 4,5]pyrrolo[3,2,1-de]acridin-11-ol (300.0 mg, 1 m ol, 1.0 eq), 2-(3-bromophenyl)pyridine (281 mg, 1.2 mmol, 1.2 eq), CuI (38 mg, 0.2 mmol, 0.2 eq), picolinic acid (49 mg, 0.4 mmol 0.4 eq) and K₃PO₄ (425 mg, 2 mmol, 2.0 eq) were added to a dry Shlenck tube equipped with a magnetic stir bar. The tube was evacuated and backfilled with nitrogen. The evacuation and backfill procedure was repeated for a total of three times. Then solvent DMSO (10 mL) was added under the protection of nitrogen. The mixture was stirred in an oil bath at a temperature of 90° C. for 3 days and then cooled down to ambient temperature, diluted with ethyl acetate. The mixture was washed with water three times and then dried over sodium sulfate and filtered. The solvent was removed under reduced pressure, and the residue was purified through column chromatography on silica gel using hexane/ethyl acetate (5:1) as and eluent to obtain the desired product Ligand ONac3 as a white solid 290 mg in 64% yield. ¹H NMR (DMSO-d, 400 MHz) for the Ligand ONac3: δ 9.32 (d, J=2.6 Hz, 1H), 8.66-8.60 (nm, 2H), 8.49 (d, J=4.4 Hz, 1H), 8.06 (d, J=7.8 Hz, 1H), 8.00 (d, J=8.4 Hz, 1H), 7.92-7.82 (m, 3H), 7.75 (d, J=8.5 Hz, 1H), 768 (d, J=8.1 Hz, 1H), 7.54 (t, J=7.9 Hz, 1H), 7.43 (t, J=7.7 Hz, 1H), 7.36 (dd, J=12.3, 7.3 Hz, 2H), 7.19 (dd, J=7.6, 1.6 Hz, 1H), 6.88 (dd, J=8.5, 2.4 Hz, 1H), 1.73 (s, 5H).

Synthesis of PdONac3

8,8-dimethyl-1-(3-(pyridin-2-yl)phenoxy)-8H-pyrido[3′,2′:4,5]pyrrolo[3,2,1-de]acridine (91 mg, 0.20 mmol, 1.0 eq), Pd(OAc)₂ (54 mg, 0.24 mmol, 1.2 eq) and n-Bu₄NBr (6.5 mg, 0.02 mmol, 0.1 eq) were added to a dry pressure tube was then taken into a glove box and acetic acid (10 mL) was added. The mixture was bubbled with nitrogen for 30 minutes and then the tube was sealed. Then the mixture was heated to reflux in an oil bath and stirred for 2 days, cooled to ambient temperature and removed the solvent. Then the solid was purified through column chromatography on silica gel using dichloromethane as eluent to obtain to obtain the desired product, PdONac3 as a white solid 46 mg in 40% yield. ¹H NMR (400 MHz, d6-DMSO): δ 8.90 (dd, J=7.5, 1.2 Hz, 1H), 8.76 (dd, J=5.6, 1.4 Hz, 1H), 8.45 (dd, J=5.2, 1.3 Hz, 1H), 8.24-8.14 (m, 2H), 8.06 (td, J=7.9, 1.5 Hz, 1H), 7.74 (d, J=7.6 Hz, 1H), 7.67 (d, J=6.7 Hz, 1H), 7.62 (dd, J=7.5, 5.6 Hz, 1H), 7.55-7.39 (m, 3H), 7.22 (t, J=7.6 Hz, 1H), 7.05 (d, J=8.3 Hz, 2H), 1.69 (s, 6H). FIG. 3 shows an emission spectrum of PdONac3 in CH₂Cl₂ at room temperature and in tetrahydro-2-methylfuran at 77K.

Example 2. Synthesis of PtNacONac Synthesis of 11,11′-oxybis(8,8-dimethyl-8H-pyrido[3′,2′:4,5]pyrrolo[3,2,1-de]acridine) (NacONac Ligand)

8,8-dimethyl-8H-pyrido[3′,2′:4,5]pyrrolo[3,2,1-de]acridin-11-ol (300 mg, 1 mmol, 1.0 eq), 11-chloro-8,8-dimethyl-8H-pyrido[3′,2′:4,5]pyrrolo[3,2,1-de]acridine (351 mg, 1.1 mmol, 1.1 eq), Pd(OAc)₂ (45 mg, 0.2 mmol, 0.2 eq), 2-Di-t-butylphosphino-3,4,5,6-tetramethyl-2′,4′,6′-triisopropylbiphenyl (144 mg, 0.3 mmol, 0.3 eq) and K₃PO₄ (425 mg, 2 mmol, 2.0 eq) were added to a dry Shlenck tube equipped with a magnetic stir bar. The tube was evacuated and backfilled with nitrogen. The evacuation and backfill procedure was repeated for a total of three times. Then solvent toulene (10 mL) was added under the protection of nitrogen. The mixture was stirred in an oil bath at a temperature of 100° C. for 3 days and then cooled down to ambient temperature, diluted with ethyl acetate. The mixture was washed with water three times and then dried over sodium sulfate and filtered. The solvent was removed under reduced pressure, and the residue was purified through column chromatography on silica gel using hexane/ethyl acetate (5:1) as and eluent to obtain the desired product Ligand NacONac as a white solid 239 mg in 41% yield. ¹H NMR (DMSO-d6, 400 MHz) for the Ligand NacONac: δ 9.30 (d, J=2.6 Hz, 2H), 8.59 (dd, J=7.7, 1.6 Hz, 2H), 8.42 (dd, J=4.8, 1.7 Hz, 2H), 8.03 (d, J=7.7 Hz, 2H), 7.74 (d, J=8.7 Hz, 2H), 7.65 (d, J=7.6 Hz, 2H), 7.42-7.37 (m, 2H), 7.31 (dd, J=7.8, 4.9 Hz, 2H). 6.91 (dd, J=8.6, 2.6 Hz, 2H), 1.71 (s, 12H).

Synthesis of PtNacONac

11,11′-oxybis(8,8-dimethyl-8H-pyrido[3′,2′:4,5]pyrrolo[3,2,1-de]acridine) (58 mg, 0.1 mmol, 1.0 eq), K₂PtCl₄ (50 mg, 0.12 mmol, 1.2 eq) and n-Bu₄NBr (3.2 mg, 0.01 mmol, 0.1 eq) were added to a dry pressure tube was then taken into a glove box and acetic acid (10 mL) was added. The mixture was bubbled with nitrogen for 30 minutes and then the tube was sealed. Then the mixture was heated to reflux in an oil bath and stirred for 3 days, cooled to ambient temperature and removed the solvent. Then the solid was purified through column chromatography on silica gel using dichloromethane as eluent to obtain to obtain the desired product, PtNacONac as a yellow solid 46 mg in 59% yield. ¹H NMR (500 MHz, d6-DMSO): δ 8.92 (dd, J=7.6, 0.9 Hz, 2H), 8.26 (dd, J=6.0, 1.0 Hz, 2H), 8.20 (dd, J=7.9, 0.7 Hz, 2H), 7.79 (dd, J=7.8, 0.6 Hz, 2H), 7.58-7.52 (m, 2H), 7.47 (d, J=8.6 Hz, 2H), 7.37 (dd, J=7.6, 5.6 Hz, 2H), 6.98 (d, J=8.5 Hz, 2H), 1.76 (s, 12H). FIG. 4 shows an emission spectrum of PtNacONac in CH₂Cl₂ at room temperature and in tetrahydro-2-methylfuran at 77K.

A number of embodiments have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of disclosure. Accordingly, other embodiments are within the scope of the following claims. 

What is claimed is:
 1. A complex of General Formula IV:

wherein: M is Pt (II) or Pd (II); each of V^(1a)-V^(1f), V^(2a)-V^(2f), V^(3a)-V^(3f), V^(4a)-V^(4c), and V^(5a)-V^(5e) is independently N, C, P, O, S or Si; each of X, X¹, and X² is independently present or absent, and each X, X¹, and X² present independently represents a single bond, CR⁷R⁸, C═O, SiR⁷R⁸, GeR⁷R⁸, NR⁷, PR⁷, PR⁷R⁸, R⁷P═O, AsR⁷, R⁷As═O, O, S, S═O, SO₂, Se, Se═O, SeO₂, BR⁷, BR⁷R⁸, AlR⁷, AlR⁷R⁸, R⁷Bi═O, or BiR⁷; Y¹ is CR, SiR, GeR, N, NR, P, P═O, As, As═O, B, BR, Al, AlR, Bi═O, or Bi; and each of R, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ is independently absent or present as a single substituent or multiple substituents, valency permitting, and each R, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ present independently represents deuterium, halogen, hydroxyl, thiol, nitro, cyano, nitrile, isonitrile, sulfinyl, mercapto, sulfo, carboxyl, hydrazino; substituted or unsubstituted: aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl, alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino, monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester, alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide, silyl, polymeric; or any conjugate or combination thereof.
 2. A light emitting device comprising a complex of claim
 1. 3. An OLED device comprising a complex of claim
 1. 4. A luminescent label comprising a complex of claim
 1. 5. A compound having one of the following structural formulas, wherein M is Pt (II) or Pd (II) and wherein each of R⁷ and R⁸, if present, independently represents hydrogen, deuterium, halogen, hydroxyl, thiol, nitro, cyano, nitrile, isonitrile, sulfinyl, mercapto, sulfo, carboxyl, hydrazino; substituted or unsubstituted: aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl, alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino, monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester, alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide, silyl, polymeric; or any conjugate or combination thereof: 